var banner = new Array();

banner[0]='https://i1236.photobucket.com/albums/ff449/leandro1A/Heroes%20Evolution/logo1.png';
banner[1]='https://i1236.photobucket.com/albums/ff449/leandro1A/Heroes%20Evolution/logo2.png';
banner[2]='https://i1236.photobucket.com/albums/ff449/leandro1A/Heroes%20Evolution/logo3.png';

document.getElementById('logo').firstChild.src= banner[Math.floor(Math.random()*banner.length)];
setInterval("document.getElementById('logo').firstChild.src= banner[Math.floor(Math.random()*banner.length)];",8000);